Panel mount connectors comprise a nonconductive housing with electrically conductive terminals securely mounted therein. Conductive leads from a discrete wire or cable are electrically connected to the terminals in the housing. The connector is configured to mate with a compatible connector on a panel or in a free hanging position within an electrical apparatus.
In many instances, the panel of the electrical apparatus may be in a somewhat uncontrolled environment. The typical panel mount connector provides little if any environmental protection such that their use in harsh environments would render the fragile and sensitive electrical terminations inoperative. Although environmentally protected electrical connectors are known, they tend to be complex multi-component structures that are relatively expensive.
Electrical connectors often are used in environments where frequent connection to the electrical apparatus and disconnection therefrom is likely. Although the connector housing and the terminals therein can be designed to accommodate frequent connection and disconnection, the connectors typically are not constructed to provide strain relief. Thus, forces exerted on the insulated leads external to the connector housing can damage the electrical connections within the housing.
Structures are known for use with electrical connectors to provide some degree of strain relief and to thereby prevent against damage due to forces exerted during the frequent connection and disconnection. Some such structures are known as backshells and surround the cable and/or connector. For example, one such backshell is shown in U.S. Pat. No. 4,125,312 which issued to Aimar on Nov. 14, 1978. The backshell shown in U.S. Pat. No. 4,125,312 includes a pair of hermaphroditic shells which can be engaged around an electrical connector. Each shell comprises a short tongue having arrays of ratchet teeth extending along opposed sides. The shells further include apertures having means for lockingly engaging such ratchet teeth. The tongues on each of the two identical shells are received in the apertures on the opposed shells as the shells are urged into a mated condition around the wires and the connector. Thus, the cooperating tongues and apertures may serve a dual function of holding the shells together and possibly achieving some degree of strain relief with respect to the wires extending into the connector. However, this construction prevents the tongues from being tightened relative to the opposed shell to increase or otherwise alter any strain relief that may be achieved by the backshell. Each shell shown in U.S. Pat. No. 4,125,312 further comprises a deflectable locking finger which engages the opposed shell. The assembled backshell structure of U.S. Pat. No. 4,125,312 defines a pair of apertures constructed to receive screws. The electrical connector is securely held in the backshell by screws extending through flanges on the connector and into the screw receiving apertures of the backshell. The backshell structure shown in U.S. Pat. No. 4,125,312 is considered undesirable in view of the complex plural components required and the poor strain relief that is achieved.
Another housing for an electrical connector backshell is shown in U.S. Pat. No. 4,358,178 which issued to Guy on Nov. 9, 1982. The backshell shown in U.S. Pat. No. 4,358,178 includes mateable housing halves which are engageable around an electrical connector. The rearward end of the backshell housing includes an aperture for receiving a multi-conductor insulated cable. Portions of the backshell housing on either side of the cable receiving portion comprise apertures for receiving a separate retcheted cable tie which can be securely received in the apertures of the housing and tightened around the cable to achieve a strain relief connection. Thus, the backshell housing shown in U.S. Pat. No. 4,358,178 also requires plural components and a separate strain relief means.
U.S. Pat. No. 4,341,431 issued to Woratyla on July 27, 1982, and also shows a multi-component backshell housing for enclosing a panel mount electrical connector. The backshell housing shown in U.S. Pat. No. 4,341,431 also includes an aperture adjacent the portion of the multi-component backshell housing through which the conductive leads extend. The aperture is dimensioned to receive a separate ratcheted cable tie which is operative to hold a plurality of insulated electrically conductive leads to the housing.
Other multi-component electrical connector backshell housings with separate strain relief means are shown in U.S. Pat. No. 4,327,956 which issued to Sitzler on May 4, 1982 and U.S. Pat. No. 4,606,596 which issued to Whiting et al on Aug. 19, 1986.
A one-piece housing intended to achieve strain relief is shown in U.S. Pat. No. 3,854,787 which issued on Dec. 17, 1984 to Snyder, Jr. The structure shown in U.S. Pat. No. 3,854,787 includes a pair of rearwardly extending generally planar surfaces which are disposed on opposite sides of an array of separately insulated conductors. These planar structures are secured to one another around the array of electrically conductive leads by separate bolts passing therethrough. This structure is substantially opened on all four sides and provides virtually no environmental protection. Furthermore, the use of separate bolts adds to costs, inventory problems and time required for mounting the housing about the connector. It is also believed that this structure would achieve very poor strain relief.
In view of the above, it is an object of the subject invention to provide an integrally molded housing for achieving strain relief engagement with an electrical connector.
It is a further object of the subject invention to provide a unitarily molded backshell structure that achieves a high degree of adjustable strain relief and that positively prevents loosening.
An additional object of the subject invention is to provide a unitarily molded backshell that environmentally protects the electrical connector.
A further object of the subject invention is to provide a backshell having an adjustable ratcheted strain relief tie that is unitarily molded with structure for securely locking the tie about the insulated conductive leads extending from an electrical connector.
Still an additional object of the subject invention is to provide a strain relief backshell that completely avoids inventory management problems.